//SamXIAO
#include <bits/stdc++.h>
using namespace std;

char s1[1000];
void f(char *x, int l)
{
		if('!' == *x) return;
		f(x+l, l++);
		printf("%c", *x);
}

void work1()
{
	int n, b;
	scanf("%s", s1);
	f(s1, 0);
}

int main()
{
	work1();
  return 0;
}
